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Background: Community-acquired pneumonia (CAP) is the major manifestation of Q fever, an emerging disease in French Guiana. Consequently, the empirical antibiotherapy used for the treatment of CAP combines doxycycline and the recommended amoxicillin. Our objectives were to estimate the prevalence of Q fever pneumonia and to build a prediction rule to identify patients with Q fever pneumonia for empirical antibiotic guidance., Methods: A retrospective case-control study was conducted on inpatients admitted with CAP in the Department of Infectious Diseases of Cayenne Hospital from 2004 to 2007. Serodiagnosis for Coxiella burnetii was performed for all patients. Risk factor analysis was performed using multivariate logistic regression, and a prognostic score was computed using bootstrap procedures. The score performance characteristics were used to choose the best prediction rule to identify patients with Q fever pneumonia., Results: One hundred thirty-one patients with CAP were included and the Q fever pneumonia prevalence was 24.4% (95% confidence interval [CI], 17.1-31.9). In multivariate analysis, male sex, middle age (age, 30-60 years), headache, leukocyte count <10 × 10(9)/L and C-reactive protein level >185 mg/L were independently associated with Q fever pneumonia. Patients with a predictive score ≤3 had a low risk of Q fever pneumonia with a negative predictive value of 0.97 (95% CI, .90-1) and a sensitivity of 0.97 (95% CI, .89-1)., Conclusions: The prediction rule described here accurately identifies patients with low risk of Q fever pneumonia and may help physicians to make more rational decisions about the empirical use of antibiotherapy. Further prospective studies should be performed to validate this score.

Background: Functional polymorphisms in immune response genes are increasingly recognized as important contributors to the marked individual differences in susceptibility to and outcomes of infectious disease. The acute sickness response is a stereotypical set of illness manifestations mediated by the proinflammatory cytokines induced by many different pathogens. The genetic determinants of severity of the acute sickness response have not previously been explored., Methods: We examined the impact of functional polymorphisms in cytokine genes with critical roles in the early immune response (tumor necrosis factor-alpha, interleukin-6, interleukin-10, and interferon-gamma) on the severity and duration of illness following acute infection with Epstein-Barr virus, Coxiella burnetii (the causative agent of Q fever), or Ross River virus., Results: We found that the interferon-gamma +874T/A and the interleukin-10 -592C/A polymorphisms significantly affected illness severity, cytokine protein levels, and the duration of illness. These cytokine genotypes acted in synergy to potentiate their influence on disease outcomes., Conclusions: These findings suggest that genetically determined variations in the intensity of the inflammatory response underpin the severity of the acute sickness response and predict the recovery time across varied infections.

An outbreak of Q fever occurred in 22 (58%) of 38 Marines deployed to Iraq in 2005. Fever (in 100% of patients), respiratory symptoms (76%), and gastrointestinal symptoms (53%) were common. Possible risk factors included dust and exposure to animals and ticks.

Background: Although hepatitis is one of the major presentations of acute Q fever, the possible influence of viral hepatitis in Q fever has, to our knowledge, never been investigated. It is an important issue in regions where Q fever hepatitis and viral hepatitis are prevalent, such as Taiwan. We conducted a study to investigate the possible influence of viral hepatitis in cases of acute Q fever hepatitis., Methods: Cases of acute Q fever confirmed by serologic examination were included in the study. All patients who were found to be positive for Q fever were tested for hepatitis B surface antigen and antibody to hepatitis C virus, and those with positive results had their viral loads determined. Demographic data, clinical manifestations, results of laboratory and imaging examinations, and responses to treatment were recorded retrospectively from charts., Results: A total of 58 patients with acute Q fever hepatitis were studied, of whom 16 (27.6%) had viral hepatitis (hepatitis B virus infection in 12 and hepatitis C virus infection in 4). Patients with and patients without viral hepatitis did not differ with regard to clinical manifestations and responses to treatment, except that chills (100% vs. 73.8%; P=.02) and nausea and/or vomiting (18.8% vs. 2.4%; P=.03) were significantly more common among patients with viral hepatitis. The change in hepatitis B and C virus loads between the acute and convalescent phase was <1.0 log(10)., Conclusions: The clinical manifestations of acute Q fever hepatitis differ little in patients with and patients without underlying viral hepatitis, and replication of hepatitis virus is not influenced by acute Q fever hepatitis.

Signs and symptoms related to the gastrointestinal tract and liver may provide important clues for the diagnosis of various tickborne diseases prevalent in different geographic areas of the United States. We review clinical and laboratory features that may be helpful in detecting a tickborne infection. Physicians evaluating patients who live in or travel to areas where tickborne diseases are endemic and who present with an acute febrile illness and gastrointestinal manifestations should maintain a high index of suspicion for one of these disease entities, particularly if the patient has received a tick bite. If detected early, many of these potentially serious illnesses can be easily and effectively treated, thereby avoiding serious morbidity and even death.

Fifteen cases of Q fever endocarditis that occurred in 1999-2000 in southern France are described and compared with 15 cases from the same area reported in 1987. Significant decreases were found in the prevalences of heart failure, hepatomegaly, inflammatory syndrome, anemia, leukopenia, and abnormal liver function test results in patients who had Q fever endocarditis after 1997. This was probably the result of a reduction in the delay before diagnosis of the disease and of the use of novel, effective antibiotic regimens.

Chronic Q fever is uncommon, with the majority of cases manifesting as culture-negative endocarditis. In this report, we describe 3 patients who present with atypical manifestations of chronic Q fever. These were a 43-year-old man whose site of chronic Q fever was the central nervous system, a 53-year-old woman who underwent coronary angioplasty 6 days before the onset of symptoms of acute Q fever and within 4 months had serologic evidence consistent with chronic Q fever, and a 66-year-old man with fever of unknown origin, a pancreatic mass, and aorto-bifemoral grafts.

Q fever is characterized by its clinical polymorphism, and pericarditis associated with Q fever has occasionally been described. Herein we report 15 cases of Coxiella burnetii pericarditis, 9 from our data bank and 6 encountered within the past 12 months. Three patients presented with life-threatening tamponade. We compare our cases with the 18 previously reported and with 60 Q fever-matched controls at our center. This study showed that Q fever pericarditis can present as acute as well as chronic disease; we describe relapse after 6 months in association with a serological profile compatible with the chronic form of disease (phase I C. burnetii IgG titer of > or = 800). Discriminant factors among patients and controls are age of > 52 years (adjusted odds ratio [OR], 5.66), the occurrence of general symptoms such as arthralgias or myalgias (adjusted OR, 6.54), and a normal erythrocyte sedimentation rate (adjusted OR, 16.37). No specific symptoms or underlying cardiac predispositions are observed.

We report a case of acute glomerulonephritis associated with acute Q fever. An abattoir worker with a nonspecific febrile illness and pneumonia and abnormal liver function test results developed hematuria, proteinuria, and acute renal failure that resolved with appropriate antimicrobial therapy. Renal biopsy demonstrated diffuse proliferative and exudative glomerulonephritis. Serological tests confirmed recent infection with Coxiella burnetii, with a fourfold rise in the titer of phase II antibody, positive phase II IgM antibody, and negative phase I antibody. Other known causes of glomerulonephritis were excluded. Most reports of renal complications of C. burnetii infection describe glomerulonephritis associated with endocarditis due to chronic Q fever. Renal involvement in patients with acute C. burnetii infection has been rarely described. Glomerulonephritis should be recognized as a complication of acute C. burnetii infection and endocarditis due to chronic Q fever.

We describe an 11-year-old boy with acute Q fever complicated by hemophagocytosis. In addition to pancytopenia, the boy presented with hyponatremia, hypofibrinogenemia, and changes in lipid metabolism. Examination of a bone marrow aspirate revealed striking hemophagocytosis. All of the pathological changes were caused by an activated macrophage system. We also discuss the possible role that pathogenetic mechanisms play in these changes.